♻️(front) improve React code quality and performance

- Remove all console.log debug statements from production code
- Fix useEffect dependency arrays (remove refs, fix dependency cycles)
- Add useMemo for sharedCalendars filtering in CalendarList
- Improve error handling in handleOpenSubscriptionModal
- Add proper cleanup pattern (isMounted) in CalendarContext
- Use i18n locale instead of hardcoded French in MiniCalendar

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/frontend/apps/calendars/src/features/calendar/components/LeftPanel.tsx

@@ -23,8 +23,7 @@ export const LeftPanel = ({
   onDateSelect,
   onCreateEvent,
 }: LeftPanelProps) => {
-  const { davCalendars } = useCalendarContext();
+  useCalendarContext();
-  console.log("davCalendars LeftPanel", davCalendars);
   return (
     <div className="calendar-left-panel">
       <div className="calendar-left-panel__create">

src/frontend/apps/calendars/src/features/calendar/components/MiniCalendar.tsx

@@ -17,9 +17,9 @@ import {
   startOfWeek,
   subMonths,
 } from "date-fns";
-import { fr } from "date-fns/locale";
 import { useTranslation } from "react-i18next";
 import { useCalendarContext } from "../contexts";
+import { useCalendarLocale } from "../hooks/useCalendarLocale";
 
 interface MiniCalendarProps {
   selectedDate: Date;
@@ -41,6 +41,7 @@ export const MiniCalendar = ({
 }: MiniCalendarProps) => {
   const { t } = useTranslation();
   const { goToDate, currentDate } = useCalendarContext();
+  const { dateFnsLocale, firstDayOfWeek } = useCalendarLocale();
   const [viewDate, setViewDate] = useState(selectedDate);
 
   // Sync viewDate when main calendar navigates (via prev/next buttons)
@@ -57,16 +58,33 @@ export const MiniCalendar = ({
   const days = useMemo(() => {
     const monthStart = startOfMonth(viewDate);
     const monthEnd = endOfMonth(viewDate);
-    const calendarStart = startOfWeek(monthStart, { weekStartsOn: 1 });
+    const weekStartsOn = firstDayOfWeek as 0 | 1 | 2 | 3 | 4 | 5 | 6;
-    const calendarEnd = endOfWeek(monthEnd, { weekStartsOn: 1 });
+    const calendarStart = startOfWeek(monthStart, { weekStartsOn });
+    const calendarEnd = endOfWeek(monthEnd, { weekStartsOn });
 
     return eachDayOfInterval({ start: calendarStart, end: calendarEnd });
-  }, [viewDate]);
+  }, [viewDate, firstDayOfWeek]);
 
   // Group days by weeks
   const weeks = useMemo(() => chunkArray(days, 7), [days]);
 
-  const weekDays = ["lu", "ma", "me", "je", "ve", "sa", "di"];
+  // Generate weekday labels based on locale and first day of week
+  const weekDays = useMemo(() => {
+    const days = [
+      t('calendar.recurrence.weekdays.mo'),
+      t('calendar.recurrence.weekdays.tu'),
+      t('calendar.recurrence.weekdays.we'),
+      t('calendar.recurrence.weekdays.th'),
+      t('calendar.recurrence.weekdays.fr'),
+      t('calendar.recurrence.weekdays.sa'),
+      t('calendar.recurrence.weekdays.su'),
+    ];
+    // Rotate array based on firstDayOfWeek (0 = Sunday, 1 = Monday)
+    if (firstDayOfWeek === 0) {
+      return [days[6], ...days.slice(0, 6)];
+    }
+    return days;
+  }, [t, firstDayOfWeek]);
 
   const handlePrevMonth = () => {
     setViewDate(subMonths(viewDate, 1));
@@ -85,7 +103,7 @@ export const MiniCalendar = ({
     <div className="mini-calendar">
       <div className="mini-calendar__header">
         <span className="mini-calendar__month-title">
-          {format(viewDate, "MMMM yyyy", { locale: fr })}
+          {format(viewDate, "MMMM yyyy", { locale: dateFnsLocale })}
         </span>
         <div className="mini-calendar__nav">
           <button
@@ -121,7 +139,8 @@ export const MiniCalendar = ({
         {/* Calendar body with weeks */}
         <div className="mini-calendar__body">
           {weeks.map((week, weekIndex) => {
-            const weekNumber = getWeek(week[0], { weekStartsOn: 1 });
+            const weekStartsOn = firstDayOfWeek as 0 | 1 | 2 | 3 | 4 | 5 | 6;
+            const weekNumber = getWeek(week[0], { weekStartsOn });
             return (
               <div key={weekIndex} className="mini-calendar__week">
                 <div className="mini-calendar__week-number">{weekNumber}</div>

src/frontend/apps/calendars/src/features/calendar/components/calendar-list/CalendarList.tsx

@@ -2,7 +2,7 @@
  * CalendarList component - List of calendars with visibility toggles.
  */
 
-import { useState } from "react";
+import { useState, useMemo } from "react";
 import { useTranslation } from "react-i18next";
 
 import type { Calendar } from "../../types";
@@ -72,6 +72,8 @@ export const CalendarList = ({ calendars }: CalendarListProps) => {
 
       if (calendarsIndex === -1) {
         console.error("Invalid calendar URL format - 'calendars' segment not found:", davCalendar.url);
+        // Reset modal state to avoid stale data
+        setSubscriptionModal({ isOpen: false, calendarName: "", caldavPath: null });
         return;
       }
 
@@ -79,6 +81,8 @@ export const CalendarList = ({ calendars }: CalendarListProps) => {
       const remainingParts = pathParts.slice(calendarsIndex);
       if (remainingParts.length < 3) {
         console.error("Invalid calendar URL format - incomplete path:", davCalendar.url);
+        // Reset modal state to avoid stale data
+        setSubscriptionModal({ isOpen: false, calendarName: "", caldavPath: null });
         return;
       }
 
@@ -92,6 +96,8 @@ export const CalendarList = ({ calendars }: CalendarListProps) => {
       });
     } catch (error) {
       console.error("Failed to parse calendar URL:", error);
+      // Reset modal state on error
+      setSubscriptionModal({ isOpen: false, calendarName: "", caldavPath: null });
     }
   };
 
@@ -105,8 +111,10 @@ export const CalendarList = ({ calendars }: CalendarListProps) => {
   // Use translation key for shared marker
   const sharedMarker = t('calendar.list.shared');
 
-  const sharedCalendars = calendarsArray.filter((cal) =>
+  // Memoize filtered calendars to avoid recalculation on every render
-    cal.name.includes(sharedMarker)
+  const sharedCalendars = useMemo(
+    () => calendarsArray.filter((cal) => cal.name.includes(sharedMarker)),
+    [calendarsArray, sharedMarker]
   );
 
   return (

src/frontend/apps/calendars/src/features/calendar/components/scheduler/Scheduler.tsx

@@ -128,7 +128,7 @@ export const Scheduler = ({ defaultCalendarUrl }: SchedulerProps) => {
       // Now trigger a re-evaluation of eventFilter by calling refetchEvents
       calendarRef.current.refetchEvents();
     }
-  }, [visibleCalendarUrls, davCalendars, calendarRef]);
+  }, [visibleCalendarUrls, davCalendars]);
 
   return (
     <>

src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useSchedulerHandlers.ts

@@ -68,19 +68,11 @@ export const useSchedulerHandlers = ({
         return;
       }
 
-      console.log('[EventDrop] Event:', info.event);
-      console.log('[EventDrop] allDay:', info.event.allDay);
-      console.log('[EventDrop] start:', info.event.start);
-      console.log('[EventDrop] end:', info.event.end);
-
       try {
         const icsEvent = adapter.toIcsEvent(info.event as EventCalendarEvent, {
           defaultTimezone: extProps.timezone || BROWSER_TIMEZONE,
         });
 
-        console.log('[EventDrop] IcsEvent start:', icsEvent.start);
-        console.log('[EventDrop] IcsEvent end:', icsEvent.end);
-
         const result = await caldavService.updateEvent({
           eventUrl: extProps.eventUrl,
           event: icsEvent,

src/frontend/apps/calendars/src/features/calendar/components/scheduler/hooks/useSchedulerInit.ts

@@ -241,19 +241,23 @@ export const useSchedulerInit = ({
     calendarRef.current = ec as unknown as CalendarApi;
 
     return () => {
+      // @event-calendar/core is Svelte-based and uses $destroy
+      // Always call $destroy before clearing the container to avoid memory leaks
       if (calendarRef.current) {
-        // @event-calendar/core is Svelte-based and uses $destroy
         const calendar = calendarRef.current as CalendarApi;
         if (typeof calendar.$destroy === 'function') {
           calendar.$destroy();
         }
         calendarRef.current = null;
       }
-      // Also clear the container
+      // Clear the container only after calendar is destroyed
       if (containerRef.current) {
         containerRef.current.innerHTML = '';
       }
     };
+    // Note: refs (containerRef, calendarRef, visibleCalendarUrlsRef, davCalendarsRef) are excluded
+    // from dependencies as they are stable references that don't trigger re-renders
+    // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [
     isConnected,
     calendarUrl,
@@ -270,15 +274,12 @@ export const useSchedulerInit = ({
     setCurrentDate,
     t,
     i18n.language,
-    containerRef,
-    calendarRef,
-    visibleCalendarUrlsRef,
-    davCalendarsRef,
   ]);
 };
 
 /**
  * Hook to check scheduling capabilities on mount.
+ * Silently verifies CalDAV scheduling support without debug output.
  */
 export const useSchedulingCapabilitiesCheck = (
   isConnected: boolean,
@@ -291,68 +292,8 @@ export const useSchedulingCapabilitiesCheck = (
 
     hasCheckedRef.current = true;
 
-    const checkSchedulingCapabilities = async () => {
+    // Silently check scheduling capabilities
-      const result = await caldavService.getSchedulingCapabilities();
+    // Debug logging removed for production
-
+    caldavService.getSchedulingCapabilities();
-      if (result.success && result.data) {
-        console.group('📅 CalDAV Scheduling Capabilities');
-        console.log(
-          'Scheduling Support:',
-          result.data.hasSchedulingSupport ? '✅ Enabled' : '❌ Disabled'
-        );
-        console.log(
-          'Schedule Outbox URL:',
-          result.data.scheduleOutboxUrl || '❌ Not found'
-        );
-        console.log(
-          'Schedule Inbox URL:',
-          result.data.scheduleInboxUrl || '❌ Not found'
-        );
-        console.log(
-          'Calendar User Addresses:',
-          result.data.calendarUserAddressSet.length > 0
-            ? result.data.calendarUserAddressSet
-            : '❌ None'
-        );
-        console.log('');
-        console.log('Raw server response:', result.data.rawResponse);
-
-        if (result.data.hasSchedulingSupport) {
-          console.log('');
-          console.log('✉️  Email Notifications Status:');
-          console.log('   The server supports CalDAV scheduling (RFC 6638).');
-          console.log(
-            '   However, this does NOT guarantee email notifications will be sent.'
-          );
-          console.log(
-            '   Email sending requires the IMip plugin to be configured on the server.'
-          );
-          console.log(
-            '   Contact your server administrator to verify IMip plugin configuration.'
-          );
-        } else {
-          console.warn('');
-          console.warn(
-            '⚠️  CalDAV scheduling properties not found on this server.'
-          );
-          console.warn('   This could mean:');
-          console.warn(
-            '   1. The scheduling plugin is not enabled in Sabre/DAV configuration'
-          );
-          console.warn(
-            '   2. The properties are located elsewhere (check raw response above)'
-          );
-          console.warn(
-            '   3. The server does not support CalDAV scheduling (RFC 6638)'
-          );
-        }
-
-        console.groupEnd();
-      } else {
-        console.error('Failed to check scheduling capabilities:', result.error);
-      }
-    };
-
-    checkSchedulingCapabilities();
   }, [isConnected, caldavService]);
 };

src/frontend/apps/calendars/src/features/calendar/contexts/CalendarContext.tsx

@@ -172,6 +172,8 @@ export const CalendarContextProvider = ({ children }: CalendarContextProviderPro
 
   // Connect to CalDAV server on mount
   useEffect(() => {
+    let isMounted = true;
+
     const connect = async () => {
       try {
         const result = await caldavService.connect({
@@ -179,18 +181,37 @@ export const CalendarContextProvider = ({ children }: CalendarContextProviderPro
           headers,
           fetchOptions,
         });
-        if (result.success) {
+        if (isMounted && result.success) {
           setIsConnected(true);
-          await refreshCalendars();
+          // Fetch calendars after successful connection
-        } else {
+          const calendarsResult = await caldavService.fetchCalendars();
+          if (isMounted && calendarsResult.success && calendarsResult.data) {
+            setDavCalendars(calendarsResult.data);
+            setVisibleCalendarUrls(new Set(calendarsResult.data.map(cal => cal.url)));
+          }
+          setIsLoading(false);
+        } else if (isMounted) {
           console.error("Failed to connect to CalDAV:", result.error);
+          setIsLoading(false);
         }
       } catch (error) {
-        console.error("Error connecting to CalDAV:", error);
+        if (isMounted) {
+          console.error("Error connecting to CalDAV:", error);
+          setIsLoading(false);
+        }
       }
     };
+
     connect();
-  }, [caldavService, refreshCalendars]);
+
+    // Cleanup: prevent state updates after unmount
+    return () => {
+      isMounted = false;
+    };
+    // Note: refreshCalendars is excluded to avoid dependency cycle
+    // The initial fetch is done inline in this effect
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [caldavService]);
 
   const value: CalendarContextType = {
     calendarRef,

src/frontend/apps/calendars/src/features/calendar/services/dav/CalDavService.ts

@@ -864,8 +864,6 @@ export class CalDavService {
         ? outboxUrl
         : `${this._account!.serverUrl}${outboxUrl.startsWith('/') ? outboxUrl.slice(1) : outboxUrl}`
 
-      console.log('[CalDAVService] Sending scheduling request to:', fullOutboxUrl)
-
       // Use fetch directly to avoid davRequest URL construction issues in dev mode
       const response = await fetch(fullOutboxUrl, {
         method: 'POST',
@@ -1208,8 +1206,6 @@ END:VCALENDAR`
     }
 
     return withErrorHandling(async () => {
-      console.log('[Scheduling Debug] Requesting from principal URL:', this._account!.principalUrl)
-
       const response = await propfind({
         url: this._account!.principalUrl!,
         props: {
@@ -1222,10 +1218,7 @@ END:VCALENDAR`
         depth: '0',
       })
 
-      console.log('[Scheduling Debug] Full PROPFIND response:', JSON.stringify(response, null, 2))
-
       const props = response[0]?.props ?? {}
-      console.log('[Scheduling Debug] Extracted props:', props)
 
       // Note: tsdav converts XML property names to camelCase
       // schedule-outbox-URL becomes scheduleOutboxURL

src/frontend/apps/calendars/src/features/calendar/services/dav/EventCalendarAdapter.ts

@@ -327,7 +327,6 @@ export class EventCalendarAdapter {
       if (isAllDay && typeof dateValue === 'string' && /^\d{4}-\d{2}-\d{2}$/.test(dateValue)) {
         const [year, month, day] = dateValue.split('-').map(Number)
         const result = new Date(Date.UTC(year, month - 1, day))
-        console.log('[EventCalendarAdapter] Parsing all-day date:', dateValue, '→', result)
         return result
       }
 
@@ -335,15 +334,12 @@ export class EventCalendarAdapter {
     }
 
     const isAllDay = ecEvent.allDay ?? false
-    console.log('[EventCalendarAdapter] toIcsEvent - allDay:', isAllDay, 'start:', ecEvent.start, 'end:', ecEvent.end)
 
     const startDate = parseDate(ecEvent.start, isAllDay)
     const endDate = ecEvent.end
       ? parseDate(ecEvent.end, isAllDay)
       : startDate
 
-    console.log('[EventCalendarAdapter] Parsed dates - start:', startDate, 'end:', endDate)
-
     // Determine timezone
     const timezone = extProps.timezone ?? opts.defaultTimezone